<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>背景颜色</title>
  <style>
    .box {
      background-color: #567895;
    }
    h2 {
      background-color: black;
      color: white;
    }
    span {
      background-color: rgb(255 255 255 / 50%);
    }
  </style>
</head>
<body>
<div class="box">
  <h2>Background Colors</h2>
  <p>Try changing the background <span>colors</span>.</p>
</div>
</body>
</html>